Not one person commenting on this mentioned the real reason. Caribou populations are in decline all over the arctic, and the reason is obvious and measurable. The climate is changing. Drastically!
Temperatures in recent decades have increased all over the arctic. Much more than at lower latitudes. Caribou time their migrations ( using light intensity and day length) to take advantage of the best new nutritious growth of forage during calving and nursing. But for the last couple decades or so, by the time the herds reach the calving grounds, the forage is over-mature and already going to seed. In their more southerly wintering grounds, the drier hotter summers have allowed many more fires which have burned vast areas of taiga forest. The caribou moss which takes as long to grow as the trees do is gone from much of their winter range - burnt and not coming back for fifty to a hundred years or so.
I have several friends who are biologists working in the North. My son is a wildfire manager working professionally in the north. They all see it. Climate change is here, it is more pronounced in the north, and the effects are obvious. Climate change is not a conspiracy or propaganda from tree huggers. Denying its happening or blaming wolves will not bring the caribou back.
We don't believe in climate change or dinosaurs.
